The sophisticated Indus Valley civilisation - which flourished four millennia ago in what is now Pakistan and western India - remains tantalisingly mysterious. At its peak, its settlements spanned an area greater than that of its contemporary in ancient Egypt. Indus jewellery was so coveted that examples have been found as far as Mesopotamia, 2500 kilometres away. Indus cities boasted blocks of houses built on a grid pattern, and drains that channelled sewage to dumping grounds outside the city walls.
Unable to decipher the Indus script, archaeologists have pored over beads, shards of pottery, and other artefacts for insights into one of the world's first city-building cultures.
A new study focuses on Harappa, one of the largest and most powerful Indus centres, with a population of up to 80,000. Researchers examined the chemical composition of teeth from a Harappan cemetery used from roughly 2550 to 2030 BCE. The analysis showed that the city was a cosmopolitan melting pot. Many of the deceased had grown up outside Harappa.
Many of the outsiders, surprisingly, are men buried near women native to Harappa. The findings are preliminary, but they suggest men moved in with their brides, even though in South Asia women traditionally move to their husband's homes. Confirmation of these early results, says lead author Mark Kenoyer of the University of Wisconsin (USA), would point to a "system where women were powerful."